This invention relates to a fastener and particularly to one that is forceably driven into a drilled hole within masonry material.
There are many instances in which there is a need to fasten a fixture or structural member to masonry material, for example a concrete floor. Various fastening systems are know such as nails driven directly into concrete without a pre-drilled hole. Various other types of fasteners are used where a pre-drilled hole is provided. For example, expandable type anchors are often used for such applications. Although expandable anchors perform well, they are costly in that they have multiple components and often require a significant amount of time to install.
This invention is related to one-piece masonry anchoring fasteners which are driven into a drilled masonry hole. Exceptional retention power is provided by the fasteners by providing features of the fastener shank which engage the wall of the drilled hole. The fasteners of this invention further incorporate features which cause them to rotate as they are driven into the hole. One embodiment features a shank made from a constant diameter wire stock which is wrapped to form a helix which defines a cylinder having a diameter greater than that of the drilled hole. In another embodiment local radial projections act as blades which define a portion of a helix for causing the fastener to rotate upon installation. In both embodiments high retention force is provided through the mechanisms of frictional engagement with the hole wall through bending deflection of the fastener, modification of the hole wall for greater surface area and conformation of the wall and fastener, and the turning of the fastener.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.